Status Update for Common Loons in Montana and Implications for Restoring Loons to Their Former Breeding Range

Abstract

The majority of the western United States’ breeding Common Loons (Gavia immer) breed on lakes located in northwestern Montana (72 pairs, 68.6%) with Washington, Wyoming, and Idaho having only 17 (16.2%), 14 (13.3%) and 2 (2.0%) territorial pairs, respectively. Recently, there have been enough continuous years of sustainable chick production in Montana (ranging between 0.66 and 0.70 chicks fledged/territorial pair) that an increase in territorial pairs is expected. Territorial pair numbers, however, have increased only slightly. Another possibility, despite loons being poor dispersers with strong breeding site fidelity, is that loons have colonized lakes south of their known breeding locations (and north of Wyoming’s breeding population). To address this possibility, in 2013, the Biodiversity Research Institute (BRI) surveyed 28 suitable lakes in southwestern Montana. No loon pairs were found on any of these lakes, suggesting loons have not expanded their range. Therefore, Montana Department of Fish, Wildlife and Parks, the Montana Common Loon Working Group, the Ricketts Conservation Foundation, and BRI are working cooperatively to investigate reasons for this finding. BRI has initiated a large-scale conservation study for the Common Loon across North America, with MT, WY, ID, and WA as a focus area. Together, these organizations hope to: further investigate these questions in the western US, to create solutions that strengthen current populations, and to one day restore loons to their former breeding range.